The present invention generally relates to recording and/or reproducing systems for 4-head type recording and/or reproducing apparatuses, and more particularly to a recording and/or reproducing system for a 4-head type recording and/or reproducing apparatus which carries out a recording and/or a reproduction by successively switching four magnetic heads which are mounted on a rotary body with a 90.degree. angular separation from each other, which recording and/or reproducing system enables reproduction by the same magnetic heads which have recorded each of the tracks on a magnetic tape.
A 4-head type recording and/or reproducing apparatus is disclosed in the specification of a U.S. patent application Ser. No. 552,721 entitled "RECORDING/REPRODUCED SIGNAL SWITCHING SYSTEM FOR A 4-HEAD TYPE RECORDING AND REPRODUCING APPARATUS" filed Nov. 17, 1983, in which the assignee is the same as the assignee of the present application. As will be described later on in the specification in conjunction with the drawings, this 4-head type recording and/or reproducing apparatus successively records a video signal on a magnetic tape which is obliquely wrapped around the peripheral surface of a drum over an angular range of approximately 270.degree., by use of four magnetic heads which are mounted on a rotary body of the drum with a 90.degree. angular separation from each other. At the time of the reproduction, the video signal is successively reproduced from the magnetic tape by these four magnetic heads. The magnetic tape having the video signal recorded thereon by these four magnetic heads, is also playable on a conventional and normal 2-head type recording and/or reproducing apparatus. In other words, the magnetic tape which is recorded by one of the 2-head type and 4-head type recording and/or reproducing apparatuses, can be played compatibly on the other of the 2-head type and 4-head type recording and/or reproducing apparatuses.
In the 4-head type recording and/or reproducing apparatus, the four magnetic heads are made up of a first pair of magnetic heads and a second pair of magnetic heads. The first pair of magnetic heads are mounted at mutually opposite positions on the rotary body, and each have a first azimuth angle. On the other hand, the second pair of magnetic heads are mounted at mutually opposite positions on the rotary body, separated from the respective first pair of magnetic heads by an angular separation of 90.degree., and each have a second azimuth angle. At the time of the reproduction, the tracks on the magnetic tape which were recorded by the magnetic head having the first azimuth angle, are reproduced by the magnetic head having the first azimuth angle. Similarly, the tracks on the magnetic tape which are recorded by the magnetic head having the second azimuth angle, are reproduced by the magnetic head having the second azimuth angle. However, even when reproducing the track by the magnetic head having the same azimuth angle as the magnetic head which recorded that track, the track which was recorded by one of the pair of magnetic heads having the same azimuth angle may be reproduced by the other of the same pair of magnetic heads.
On the other hand, even between the magnetic heads having the same azimuth angle, the magnetic heads do not have exactly the same characteristic because of the inconsistencies introduced when the magnetic heads are manufactured. In other words, the magnetic heads having the same azimuth angle, actually have characteristics which differ within an allowable range. Accordingly, there is a problem that an optimum reproduced output cannot be obtained when the track which was recorded by one of the pair of magnetic heads having the same azimuth angle, is reproduced by the other of the same pair of magnetic heads.